Best Way to Limit Groups of HITs to One Worker Per Any HIT Included in the Group?

Question

I would like to limit a group of MTURK HITs such that if a worker has taken any previous HIT included in the group, he or she cannot take any future hits included in the group.

I have seen two distinct methods of doing this described here on StackOverflow.

1. Use qualifications. https://stackoverflow.com/a/16415447/364966

2. Have the HIT check with a function on your server and if a worker has taken a previous HIT from the group, politely inform the worker that the hit won't be available. https://stackoverflow.com/a/3782847/364966 and https://stackoverflow.com/a/13851920/364966

One poster on StackOverflow commented that "I used to do this with qualifications, but found that it really limited participation." https://stackoverflow.com/a/3782847/364966

Is it better to use method #1 or method #2? Or, are both methods equally viable?

Answer 1

The easiest thing to do is just have one ExternalQuestion HIT that you host on your own server, wherein you serve up different content to each worker. In lieu of your own server, you can do this with javascript as well but the reliability might be reduced and you have to design it well to accommodate workers viewing the HIT in "preview" mode.

So, I would not do either of the suggested strategies you point to (and this is coming as the person who posted the answer #1 that you refer to in your question.)